Technical Field
The present invention relates to a method for feeding electrical energy into an electrical supply grid by means of a wind turbine or wind farm. The present invention, moreover, relates to a wind turbine for feeding electrical energy into an electrical supply grid, and the present invention relates to a wind farm for feeding electrical energy into an electrical supply grid.
Description of the Related Art
Feeding electrical energy into an electrical supply grid by means of wind turbines or by means of a wind farm comprising several wind turbines is a matter of common knowledge. It is also known that the wind turbine or wind farm is not only responsible for feeding energy, but also for grid support. So, what is assumed here as an AC grid is a common electrical supply grid.
An early document that describes grid support by means of wind turbines is, for example, U.S. Pat. No. 6,965,174. This document describes, inter alia, the adjustment of the phase angle when feeding energy by means of a wind turbine. Later documents, such as document U.S. Pat. No. 7,638,893, also describe methods for a wind farm.
Such methods monitor the grid and possibly respond to changes in the grid. Nowadays, the share of wind energy in the grid has increased substantially, at least in some states or regions, so that the feeding of energy, and thus possibly also grid stability, may depend more and more on the prevailing wind conditions. This problem can be met by a temporary storing of energy. Such temporary storage systems may be, however, costly and often are not available in sufficient quantities, or at all.
The German Patent and Trademark Office has researched the following prior art: DE 10 2010 006 142 A1, U.S. Pat. No. 6,965,174 B2, U.S. Pat. No. 7,638,893 B2 and US 2011/0148114 A1.